How to distribute animated meshes with a particle system
I got it to duplicate the animated mesh. I did not have to instance the armatures with the mesh. At first, it wasn't working for me either. It only duplicates the animated mesh if the original animated meshes are visible in the scene. I presume you have them in a separate layer. Try making that layer visible.

This seems like a workaround though. It would be nice to have the original objects invisible. Maybe you should file a bug report for this?